Colorectal cancer (CRC) is the second leading cause of cancer death in Western countries (American Cancer Society 2000). It is estimated that in the United States approximately 57,000 people will die from colorectal cancer in 2003 (Cancer Facts and Figures 2003, American Cancer Society, 2003). In recent years epidemiological studies have shown that consumption of a diet containing fruits and vegetables rich in antioxidants is linked to lower incidence of colon cancer (Yang et al., 2001, Annu Rev Nutr., 21:381-406). Many of the compounds in fruits and vegetables such as vitamins, minerals, phytochemicals are defined as dietary supplements (Dietary Supplement Health and Education Act, 1994). Among colorectal cancer patients it is reported that 64% use alternative medicine of which 57% take some kind of dietary supplement (Patterson et al., 2002, J. Altern Complement Med, 8:477-485). Various phytochemicals in fruits and vegetables have been shown to inhibit colon cancer development in animal model studies.
There remains a need for identifying natural compounds, phytochemicals and food extracts that are effective as chemopreventatives against cancer, including colon cancer. The present inventors have discovered that compositions comprising anthocyanin-rich extracts are effective for inhibiting cancer cell growth, and have further discovered methods for specifically inhibiting the growth of colon cancer cells without inhibiting the growth of normal colonic cells.